The fiasco of the Patient Protection and Affordable Care Act rollout says a lot about the hubris and incompetence of Barack Obama's White House and about the values and priorities of the Republican opposition — points that haven't gone unnoticed. I'm struck, though, by something that's received less attention. In the Obamacare debacle, you see the results of a more far-reaching failure.

Why were so many stupid, avoidable mistakes made during the preparations for the debut of HealthCare.gov? Why did they go undetected until it was too late? Why did Obama even dare to make his promise that all who wanted to keep their insurance would be able to? Why did it come as such a shock when that promise turned out to be false — as a moment's thought at any point would have told you it was bound to be?

Political dysfunction is part of the answer — though only part. The war between the administration and the House of Representatives is only the starting point.

Obamacare was passed by the narrowest possible margin in the face of solid Republican opposition. With no buy-in from the other side, the reform law was exposed from the start to continuous and intense enemy action.

This had consequences. Preparations for its introduction — and any glitches in the preparations — had to be hidden from public view. Crucial decisions were postponed for fear of unwanted scrutiny. Full testing of the website, incredible as this seems, was delayed until days before it went live. By then, politics ruled out any postponement regardless of what the testing found.

The war between the parties also explains Obama's false promise about letting people keep their insurance — not just that he made the promise in the first place, but also (which is even stranger) that Republicans in Congress didn't call him on it when he did. Given the public's skepticism, intense opposition and his reluctance to explain the health care law to the country, Obama had to lie to get it passed. A little dishonesty was justified, he believed, because the country would like the policy once it was up and running (as indeed the country still might).

But why did Republicans fail to challenge him on the promise? Because that objection was too small to be worth making. You wouldn't criticize communism for, say, narrowing shoppers' choices. Obamacare had to be deplored, not criticized. It had to be denounced, however ludicrously, as a kind of coup — a government takeover of the U.S. health care system.

Democrats wouldn't be so unreasonable? Think of privatizing Social Security. You don't meet an atrocity of that kind halfway by saying, "In fact, it won't be quite that simple. Some people could be worse off." You call it a plot to impoverish the elderly. As for suggesting ways to improve the idea, forget it. That's just enabling the enemy.

In this way, from one election to the next, exaggerated polarization causes politics to collapse into sound and fury signifying nothing. This is why, annoying as they can be, you sometimes need centrists. Without them, opposition can be so furious that it's pointless. And the result is a breakdown of effective accountability.

This cost of excessive polarization is real. Michael Lind, among many others, writes that polarized politics in the United States is nothing new and no big deal. This claim has become almost as much of a cliché as the view that polarization is the root of all the country's problems. Lind concedes that the parties have become more tightly sorted — there are no more conservative Democrats or liberal Republicans — but says the ideological gap between conservatives and liberals hasn't changed that much.

Actually, it's plausible that tighter partisan sorting increases ideological polarization. Even if it didn't, Lind is missing the point: Greater partisan polarization would still be a problem, because it narrows the range of debate within the parties and militates against constructive criticism of opposing views. Partisan rivalry is meant to improve policy. That's one of its purposes. Once a certain level of estrangement is achieved, rivalry stops helping and starts hurting. You couldn't ask for a clearer case than health care reform.

However, this is not just about Congress and the White House. Where was expert opinion, inside or outside the government, on the challenges of getting the website to work, or on the likelihood of policy cancellations, or on the many other problems of execution the reform was likely to face? And where was the U.S. commentariat on those subjects? Why so few skeptical supporters? Why so few sympathetic opponents?

This vacuum of uncommitted opinion explains what would otherwise be a puzzle. Countless words have been written on the case for and against Obamacare, yet the perfectly foreseeable problems of the past two months took almost everybody — advocates and opponents alike — by surprise.

The curse of U.S. politics is not just that it's polarized but also that there's so damned much of it. Unaligned expert opinion is hard to find. Unaligned commentators are even rarer. Top jobs in the civil service, several layers down into the bureaucracy, are given to political appointees. Experts brought into government for specific projects are required to be Democrats or Republicans first, and experts second: They become another species of politician.

Don't expect much help from my industry. America's most read commentators on public policy have all, to a greater or lesser extent, decided which team they're on. On health care, as on everything from climate change to abortion, pundits are sorted as thoroughly as professional politicians — they're either champions of the reform, dedicated to advancing its prospects despite whatever reservations they might have about the details, or furious critics, determined to kill it regardless of any feeling they might have for the chronically ill who can't buy insurance.

In one way, this state of affairs is unremarkable in a country that also elects prosecutors and judges (though not, apparently, dogcatchers). But in a system that's all politics, all the time, you've got quite a problem when politics turns toxic.

On health care, the entire country has been engaged in a dialogue of the deaf. I know, I know: It was ever thus. Still, it seems to me to be getting worse. And new or old, it surely comes at a cost. I don't see how anybody could look at the Obamacare shambles and deny it.